Real-time arrivals for some NYC subway lines now accessible on iPhone (Updated)

Update: The capable (not to mention iPhone 5- and Retina-aware) subway scheduler app NextStop has been updated to include the realtime info for the relevant lines. It's a much prettier and effective way to get at this info than the MTA's app, which should be considered a beta at best and a technology demonstration at worst.

The Second Avenue Sagas subway blog has a quick take on the app, pointing out the features and flaws of the MTA's approach. On the plus side, the app and the companion website deliver the same data that appears on platform next-train clocks, giving riders the best possible chance to make their trains. Unfortunately, without cellular or WiFi access, you're stuck with the estimated timetables used by apps like Embark, iTrans and NextStop.

Aside from the network access challenge and the rather utilitarian design of the app (not optimized for iPhone 5), other issues are somewhat more deeply knotted into New York's subway infrastructure.

Rather than the reasonably modern and automated switching systems used on mass transit networks built out in the 1960s and later, most of New York's subway lines are still controlled via fixed-block signaling that was leading-edge back in the 19th century. That's why only the A Division lines (the legacy IRT lines, with numbered designations, plus the 42nd Street Shuttle) are getting this real-time support now; they have the signal upgrades that provide live train progress. Other lines with upgraded signaling already done (the L train) or planned (the 7 line) will be joining the app's list when ready, but the remainder of the system could be stuck in the data drought for years or decades until the signaling overhauls are complete.

The MTA knows that third-party developers are eager to make use of this real-time train schedule data, and indeed those working on their own apps can get access to the live feed. Keep an eye out for updates to NYC transit apps early in 2013 featuring live train schedules.